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7 Reasons A Split System AC Is Not Blowing Cold Air And How To Fix It

If you rely on your split system air conditioner to keep cool, it can be a problem when it stops blowing cold air. This issue can be caused by a 7 common factors. This guide will assist you in diagnosing and resolving the problem of a split system AC not blowing cold air.

Split AC not blowing cold air

Understanding a Split System AC

Split system air conditioners consist of two main parts: an outdoor unit that contains the compressor and condenser, and an indoor unit that houses the evaporator and air handler. The indoor unit blows cool air into your home, while the outdoor unit expels heat from the refrigerant. Any disruption in this process can lead to your AC not blowing cold air.

Split system AC - 2 main parts

7 Reasons Why Split AC Blows No Cold Air?

  1. Air filters
  2. Condenser
  3. Thermostat
  4. Airflow
  5. Electrical
  6. Evaporator coil
  7. Refrigerant

What Causes AC Not Blowing Cold Air?

1. Dirty Air Filters

If the air filters of your AC unit are dirty, they can block the flow of air, preventing it from being cooled efficiently. This results in a noticeable decrease in the AC’s cooling performance. Regular cleaning or replacement of the filters can help alleviate this problem.

Here is a step by step guide for how to properly clean your split system AC air filter:

  1. Turn off the AC Before starting, ensure the AC unit is turned off to prevent any accidents.
  2. Open the AC unit Most split system AC units have a front panel that opens upwards. Gently lift this up to reveal the air filters.
  3. Remove the filters The filters should easily slide out. Be careful not to damage them as they can be delicate.
  4. Check the filters If they’re covered in dust, they need cleaning. If they’re damaged, they need replacing.
  5. Clean the filters If they’re just dusty, gently tap them to knock off the excess dust. For a deeper clean, use a vacuum cleaner with a brush attachment. If they’re very dirty, you can wash them in warm water with a mild detergent. Let them soak for about 15 minutes, then rinse thoroughly.
  6. Dry the filters After washing, let them air dry completely. Don’t put them back in the AC unit while they’re still wet as this can cause problems.
  7. Reinstall the filters Once they’re dry, slide them back into the AC unit.
  8. Close the AC unit Lower the front panel back into place.
  9. Turn on the AC Now your AC should run more efficiently with clean air filters.

Remember, it’s generally recommended to clean your AC filters every 1-3 months, depending on usage and air quality in your area.

2. Condenser Blocked

The condenser is a crucial component of an AC unit that dissipates heat to the outdoors. If it’s blocked or damaged, the heat exchange process will be disrupted, leading to an inability to cool the air. You may need to have the condenser cleaned, repaired, or replaced.

Cleaning the condenser of a split system AC involves several steps. Here’s a step-by-step guide:

  1. Turn Off the Power For safety reasons, turn off the power to the unit. This might require turning off the circuit breaker that supplies electricity to your outdoor unit.
  2. Remove Debris Before you begin cleaning the condenser, remove any visible debris (leaves, grass, dirt, etc.) from the exterior of the unit.
  3. Remove the Outer Cover Usually, there are screws on the top and sides of the unit that hold the cover in place. Unscrew these and lift the cover off the unit. Be careful not to damage any wiring connected to the cover.
  4. Clean the Fins The fins are the thin, metallic blades that cover the unit. Use a soft brush to gently remove any dust or debris from the fins. You can also use a fin comb, specifically designed for this task.
  5. Straighten Bent Fins If any fins have been bent, they can restrict airflow. Use a fin straightening tool to carefully realign them.
  6. Clean Around the Unit Once the fins are clean, check around the unit and remove any debris that could clog the system.
  7. Clean the Inside Use a coil cleaner available at most home improvement stores. Follow the instructions on the package to apply and rinse the cleaner.
  8. Replace the Cover Reinstall the cover and secure it with the screws you removed earlier.
  9. Restore Power Turn the power back on at the circuit breaker.

3. Thermostat Issues

The thermostat measures the room’s temperature and controls the AC’s operation accordingly. If it’s not functioning correctly, it may not signal the AC to cool the air when necessary. Troubleshooting and fixing your thermostat can resolve this problem.

The thermostat controls the temperature settings of your AC unit. Here are the steps to troubleshoot:

  1. Check the Power Source Ensure that the thermostat and the AC unit both have power. Check the circuit breaker and reset it if it has tripped.
  2. Inspect the Thermostat Look at your thermostat. If it’s a digital one, the screen should be lit. If it’s not, it might require new batteries. Replace them if necessary.
  3. Check the Temperature Setting Make sure the thermostat is set to cool and that the temperature is set below the room temperature. If not, adjust it accordingly.
  4. Examine the Wires If your thermostat still isn’t working, turn off the power to your AC and remove the cover of your thermostat to check the wiring. Look for any loose or corroded wires. If you find any, tighten or replace them.
  5. Clean the Inside of the Thermostat Dust and dirt can interfere with the thermostat’s functionality. Use a soft brush to gently clean the inside.
  6. Reset the Thermostat Some thermostats have a reset button. If yours does, try pressing it to reset the thermostat.
  7. Check for Drafts If the thermostat is located near a source of heat or cold air, it may not accurately read the room’s temperature. You may need to relocate it if this is the case.

4. Insufficient Airflow

If there’s not enough airflow in the room, the AC may struggle to cool the air efficiently. This could be due to blocked vents or a problem with the fan. Ensuring good airflow and fixing any fan issues can help.

Fixing insufficient airflow issues on a split system AC involves several steps. Here’s a step-by-step guide:

  1. Check the Air Filters The first step is to check the air filters. If they are clogged or dirty, they can block the airflow. You should clean or replace them if necessary.
  2. Inspect the Ductwork Next, check the ductwork for any leaks or blockages. If you find any, you should seal or repair them as necessary.
  3. Examine the Thermostat Sometimes, the thermostat might be set at a high temperature, making the AC work harder and reducing the airflow. Ensure it’s set at the right temperature.
  4. Check the Outdoor Unit The outdoor unit might be blocked by debris or dirt, reducing the airflow. You should clean it regularly.
  5. Look at the Fan The fan in the indoor unit might be malfunctioning, which can reduce the airflow. If this is the case, you might need to repair or replace it.
  6. Check the Coils The coils in the outdoor unit might be dirty or blocked, which can reduce the airflow. You should clean them regularly.

Fix A Mini Split AC Not Blowing Cold

5. Electrical Issues

If there’s an issue with the AC unit’s electrical system, it might not function properly. This could be due to a blown fuse, a tripped breaker, or a wiring issue. An electrician can help diagnose and fix these problems.

Fixing electrical issues on a split system AC can be a big task. If you’re not comfortable with doing this, it’s best to hire a professional. However, if you have basic electrical knowledge, you can follow these steps:

  1. Power Off the Air Conditioner Turn off the circuit breaker of your AC unit to ensure safety while checking the electrical components.
  2. Inspect the Circuit Breaker Check the circuit breaker for any tripped circuits. If it has tripped, try resetting it. If it trips again, it indicates a more serious electrical issue.
  3. Check the Fuses Most AC units have a fuse box. If the fuse is blown, replace it with a new one of the same rating.
  4. Inspect the Wiring Look for any signs of wear and tear, corrosion, or disconnection. You might need to replace damaged wires. Always ensure that the connections are tight and secure.
  5. Check the Capacitor The capacitor stores the energy needed to start the AC unit’s motor. If it’s faulty, your AC might not be able to start. Use a multimeter to check the capacitor’s condition. If it’s defective, replace it.
  6. Examine the Contactor The contactor controls the flow of electricity to different parts of the AC. If it’s burnt or pitted, it might need a replacement.
  7. Check the Thermostat Inspect the thermostat for any potential wiring issues. If it’s not working properly, it might not send the right signals to the AC unit.
  8. Inspect the Motor If the motor is not running, it could be due to an electrical issue. Use a multimeter to check the motor for continuity. If it’s faulty, you’ll need to replace it.

6. Evaporator Coil Freeze

If the evaporator coil freezes, it can’t absorb heat as it should, leading to less cool air being blown out. This could be due to low refrigerant levels or insufficient airflow. Fixing these issues can help prevent the coil from freezing.

A frozen evaporator coil can prevent your AC from cooling. Here’s how to fix it:

  1. Turn Off the AC Unit Before doing anything, ensure the AC unit is turned off to avoid causing any further damage.
  2. Thaw the Frozen Coil You can thaw the coil by running the fan on your AC system or using a hairdryer at the lowest setting. Never try to scrape or chip away the ice; this can lead to further damage.
  3. Check the Filter A dirty air filter can restrict airflow to the evaporator coil, causing it to freeze. Replace the air filter if it’s dirty.
  4. Inspect the Ductwork Make sure all the ducts are open and unblocked. Restricted airflow can also cause the coil to freeze.
  5. Check the Refrigerant Level A low refrigerant level can cause the coil to freeze. If you suspect this is the issue, it’s best to call a professional as handling refrigerant requires special certification.
  6. Inspect the Thermostat Ensure the thermostat is functioning correctly. If it’s set too low, it could cause the evaporator coil to freeze.
  7. Check the Drain Pan and Condensate Line Ensure the drain pan isn’t overflowing and the condensate line isn’t clogged. If either is the case, it could contribute to a frozen coil.

7. Low Refrigerant Levels

The refrigerant in your AC unit is responsible for cooling the air. If the refrigerant level is low, perhaps due to a leak, the AC will not be able to cool the air effectively. Fixing any leaks and refilling the refrigerant can solve this issue.

Fixing low refrigerant levels in a split system AC is a slightly complex task that may require professional help, but here are some steps that can guide you:

  1. Safety Precautions Before you start any work on your split AC system, make sure to turn off the power for safety reasons.
  2. Identify Symptoms Low refrigerant levels can cause several symptoms, such as a loss of cooling capacity, higher energy bills, or ice build-up on the evaporator coils. If you notice any of these symptoms, you may need to check your refrigerant levels.
  3. Check for Leaks Low refrigerant levels are often caused by leaks. You can check for leaks by looking for oily residue around AC fittings and connections. A more accurate method is to use a leak detection kit, which involves adding a UV dye to the system and using a UV light to spot any leaks.
  4. Repair Leaks If you find a leak, it needs to be repaired before adding more refrigerant. This can be a complicated process that involves brazing pipes and fittings, so you may want to hire a professional.
  5. Recharge the System Once any leaks are repaired, you can recharge the system with refrigerant. This involves connecting a refrigerant cylinder and a manifold gauge set to your AC system, then slowly adding refrigerant until the recommended level is reached.

This guide can apply to the following most popular split system AC models:

Mitsubishi – MZ-GL12NA
LG – LS120HEV2
Fujitsu – ASU9RLF1
Panasonic – CS-E12RB4UW
Carrier – 38MGRQ18B–3 / 40MBDQ18–3
Toshiba – RAS-12N3KV2-A
Hitachi – RAS25YHA
Trane – 4MXW6-A
Samsung – AQV12PSD
Gree – VIR09HP115V1B
Bosch – BMS500-AAU024-1AHXXA
Haier – HSU-18TFF
Whirlpool – WSPR1B
Blue Star – IC315AATU
Voltas – 173V JZJ
Godrej – GIC 18YTC3-WTA
Sanyo – SI/SO-15T3SCIA
Hisense – AS-12UR4SVETG01

Always refer to your AC unit manual for specific details.

A split system AC not blowing cold air can be caused by several issues, from dirty air filters to faulty parts. Regular AC maintenance can prevent many of these issues before they become serious problems.

If you need assistance you can leave a comment below and we can assist you with your split system not blowing cold air.

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